Support ARM

[ekcasey]

GOAL: Support buildpack builds for ARM images

** WARNING** Not yet ready to implement, may require RFCs, spec changes and/or imgutil changes.

Lifecycle Behavior

analyzer

1. If the previous image is a multiarch image, select the child manifest that matches the runtime architecture of the build environment.
2. Warn and proceed without analyzing the previous image if there the image exists but has the wrong architecture.

Because analyzer may run in a lifecycle image rather than in the build environment the runtime architecture of the analyze phase may not match the build environment. We need an RFC to either:

1. Record the information in detector and pass it to analyzer.
2. Accept an -arch flag and fail if the previous image is a multiarch image and the -arch flag is not provided by the platform

exporter

1. If the run-image is a multiarch image, select the child manifest that matches the runtime architecture of the build environment.
2. Fail if there is no run-image with the correct architecture
3. If there was a previous image, validate that the previous image architecture and the run image architecture match.

Because exporter may run in a lifecycle image rather than in the build environment the runtime architecture of the analyze phase may not match the build environment. We need an RFC to either:

1. Record the information in a previous phase and pass it to analyzer.
2. Accept an -arch flag and fail if the previous image is a multiarch image and the -arch flag is not provided by the platform

rebaser

1. If the run-image is a multiarch image, select the child manifest that matches the app image architecture
2. If the run-image is not a multiarch image rebaser should validate that the architecture matches the app-image before rebasing.

Lifecycle Artifacts

Publish ARM lifecycle artifacts

Add the following new Makefile targets:

• make build-linux-x86-64
• make build-linux-arm64
• make build-windows-x86-64
• make build-windows-arm64
• make package-linux-x86-64
• make package-linux-arm64
• make package-windows-x86-64
• make package-windows-arm64
  Binaries should end up in out/<os>/<arch>.

And update the existing targets:

• make build-linux -> make build-linux-x86-64 && make build-linux-arm64
• make build-windows -> make build-windows-x86-64 && make build-windows-arm64
• make package-linux -> make package-linux-x86-64 && make package-linux-arm64
• make package-windows -> make package-windows-x86-64 && make package-windows-arm64

Local ARM image builds

Add the following new Makefile targets:

• make build-image-linux-amd64
• make build-image-linux-arm64
• make build-image should create a multiarch image containing a windows image and both linux architectures.

Docker desktop should support both building for multiple architectures. I do not know if a daemon running on a x86 linux machine will allow us to load arm64 images.

Note We cannot publish arm windows images becausemcr.microsoft.com/windows/servercore:ltsc2019 does not include an arm manifest (unlikemcr.microsoft.com/windows/nanoserver:1809 which we recently moved away from).

Publish ARM images

Instead of publish buildpacksio/lifecycle:<commit>-linux images for each build, publish

• buildpacksio/lifecycle:<commit>-linux-amd64
• buildpacksio/lifecycle:<commit>-linux-arm64

The buildpacksio/lifecycle:<commit> multiarch image should contain the windows image and both linux architectures.

When we release a new lifecycle version we should retag appropriate images with

• buildpacksio/lifecycle:<version>-linux-amd64
• buildpacksio/lifecycle:<version>-linux-arm64
• buildpacksio/lifecycle:latest-linux-amd64
• buildpacksio/lifecycle:latest-linux-arm64

And ensure that both buildpacksio/lifecycle:latest and buildpacksio/lifecycle:<version> include both linux architectures.

[dfreilich]

This issue focuses on support for arm64. There's an issue open by pack (buildpacks/pack#907) re: arm64 and armv7 support – should I open a separate issue for armv7, or can we tack that on to this?

[dfreilich]

Also, for clarity sake, what RFC(s) would you imagine we would need to drive this through?

[natalieparellano]

Possibly relevant exploration around building ARM images on x86: https://github.com/buildpacks/samples/pull/60/files

[dfreilich]

Would we need separate lifecycle images for darwin/arm64 as well? If so, should I open up a new issue for that? Related: buildpacks/pack#1003

[tibeer]

Ran into this issue today. Just for your information: I do not use lifecycle directly but rather by trying to use Hashicorps waypoint to spin up a Kubernetes deployment (of any container) on my local Kubernetes cluster. I am working on a M1 Mac.